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View Full Version : A4 downshift double surge???



SSpdDmon
June 22nd, 2005, 12:34 AM
Has anyone ever experienced this? When I'm cruising along at 65~70mph and floor it, the trans jumps into 2nd for the last few rpms of that gear. It kicks/jumps like any other downshift. But, after about .5 seconds it kicks again like it disengages and re-engages the drivetrain briefly. One of my logs shows the downshift where the VSS is at 68mph and the initial kick is pushing the car to 72mph. Then the car accelerates to 75mph just before it feels like something disengages. The VSS drops to 73mph during this second kick. When it feels like power is fully restored to the drivetrain (like the original downshift kick), the car takes off for the remainder of 2nd gear. It's hard to tell if this is spark related, torque management/abuse mode related, TCC related, etc. Are there any parameters/tables that would cause this either in the engine or trans settings? I would like to get a grip on this before I start tweaking the trans settings too much.

joecar
June 24th, 2005, 07:00 AM
Post a log chart showing:
VSS
RPM
SPARK
TP
MAF
MAP
IAT
ECT
TFT
PRND
Current Gear
PCS
last shift time
last shift error
TCC PWM

and also these pids or state pids (I can't look them up right now...):
TCC flags
brake pedal switch flag
3-2 solenoid

Be sure to be logging in 10 fps mode.